Hi pw154,
If you are designing and building your own mattress out of separate components the first place I would start is by reading option 3 in post #15 here and the posts it links to so that you can make sure that you have realistic expectations and that you are comfortable with the uncertainty and trial and error (or in some cases higher costs) that may be involved in the DIY process. The best approach to a DIY mattress is a “spirit of adventure” where what you learn and the satisfaction that comes from the process itself is more important than any cost savings you may realize (which may or may not happen).
This is particularly true with polyfoam mattresses because there are many factors and “specs” involved in assessing the firmness level of polyfoam layers besides just IFD (see post #4 here) (although the mattress you listed would be a memory foam mattress not a polyfoam mattress because the comfort layer is memory foam).
[quote]I am in Canada and have found a source through your mattress forum (en.memoryfoamcomfort.ca) out of Quebec that sells high resilience poly foam 2.5 lbs, with a support factor of 2.8.
That being the case, I have this particular configuration in mind:
3" - Soft 14 ILD 5 lbs Aerus Visco Memory Foam
3" - Medium-Firm 28 ILD 2.5 lbs High Resilience Poly Foam
6" - Firm 35 ILD 2.5 lbs High Resilience Poly Foam[/quote]
As you probably know Memory Foam Comfort is one of the members of this site which means that I think highly of them and the quality and value of their mattresses along with their knowledge and experience so they would be well worth talking to. These are certainly all very high quality materials and there are no “weak links” in the design in terms of durability.
When you can’t test a specific combination of layers or a specific mattress in person before a purchase though I would always make sure you have a more detailed conversation with the manufacturer or retailer so they can “talk you through” the suitability of your choices because most people would have little idea of how all the different types of materials and specs would actually “feel” in real life or interact together … (see mattress firmness/comfort levels in post #2 here) and this is especially true with polyfoam (although again your mattress would be a “memory foam” mattress). They will have much more knowledge and experience with the materials and mattresses they sell than anyone else and are in the best position to provide “expert guidance” about their products and how the different combinations would likely feel and perform for different body types and sleeping positions. Even experienced mattress designers are often surprised at the difference between how a particular combination of materials “should feel” based on theory or specs compared to how it actually does feel in “real life”.
I would also keep in mind that polyfoam ILD is not comparable to latex ILD because they are measured in different ways (see post #6 here) and that ILD is not particularly meaningful with memory foam at all because ILD testing with memory foam produces different numbers because it’s a slow response material and the ILD of memory foam changes with temperature, humidity, and the length of time it is compressed.
Yes … any good quality stretch knit cover such as the SleepEz cover would be a suitable choice for a memory foam mattress.
Phoenix